Dynamoelectric machine having encapsulated coil structure with one or more of phase change additives, insert molded features and insulated pinion

Abstract

Magnet wires wound in slots in a lamination stack of a dynamoelectric machine are encapsulated, in whole or in part, with thermally conductive plastic. Pre-formed features having a thermal conductivity higher than the thermally conductive plastic are insert molded when the plastic is molded. The pre-formed features may include a finned end cap and a fan. Alternatively, end domes of the plastic over end coils of the wound magnet wires have a metallic layer on them, such as by being metallized. The end domes can be formed with features which are also metallized. The thermally conductive plastic can have a phase change additive in it. The magnet wires can have a layer of heat activated adhesive that is activated when the plastic is molded. Slots in the lamination stack can include slot liners formed of thermally conductive plastic. A fan can be formed when the thermally conductive plastic is molded to encapsulate the magnet wires.

1. An armature for an electric motor, comprising:
 a shaft having a lamination stack thereon;  
 the lamination stack having a plurality of slots in which magnet wires are wound forming coils having end coils at opposed ends of the lamination stack;  
 thermally conductive plastic molded around the coils including the end coils; and  
 at least one feature pre-formed of material having a thermal conductivity higher than that of the thermally conductive plastic insert molded on at least one of the end coils when the plastic is molded so that it is disposed on an outer surface of the end coil.  
 
     
     
       2. The armature of  claim 1  wherein the feature includes at least one end cap. 
     
     
       3. The armature of  claim 2  wherein the feature further includes a fan. 
     
     
       4. The armature of  claim 1  wherein the feature includes fins. 
     
     
       5. The armature of  claim 1  wherein the slots of the lamination stack includes slot liners made of thermally conductive plastic. 
     
     
       6. The armature of  claim 1  wherein the magnet wires have a layer of heat activated adhesive thereon, the thermally conductive plastic molded around the magnet wires and the heat of the thermally conductive plastic as it is molded activating the heat activated adhesive on the magnet wires and bonding the magnet wires together. 
     
     
       7. The armature of  claim 1  wherein at least one fan is formed of the thermally conductive plastic when the thermally conductive plastic is molded to at least partially encase the magnet wires. 
     
     
       8. An electric motor including an armature and a stator, the armature, comprising:
 a shaft having a lamination stack thereon;  
 the lamination stack having a plurality of slots in which magnet wires are wound forming coils having end coils at opposed ends of the lamination stack;  
 thermally conductive plastic molded around the coils including the end coils; and  
 at least one feature pre-formed of material having a thermal conductivity higher than that of the thermally conductive plastic insert molded on at least one of the end coils when the plastic is molded so that it is disposed on an outer surface of the end coil.  
 
     
     
       9. The apparatus of  claim 8  wherein the feature includes at least one end cap. 
     
     
       10. The apparatus of  claim 9  wherein the feature further includes a fan. 
     
     
       11. The apparatus of  claim 8  wherein the feature includes fins. 
     
     
       12. The apparatus of  claim 8  wherein the slots of the lamination stack includes slot liners made of thermally conductive plastic. 
     
     
       13. The apparatus of  claim 8  wherein the magnet wires have a layer of heat activated adhesive thereon, the thermally conductive plastic molded around the magnet wires and the heat of the thermally conductive plastic as it is molded activating the heat activated adhesive on the magnet wires and bonding the magnet wires together. 
     
     
       14. The apparatus of  claim 8  wherein at least one fan is formed of the thermally conductive plastic when the thermally conductive plastic is molded to at least partially encase the magnet wires. 
     
     
       15. A power tool having an electric motor including an armature and a stator, the armature, comprising:
 a shaft having a lamination stack thereon;  
 the lamination stack having a plurality of slots in which magnet wires are wound forming coils having end coils at opposed ends of the lamination stack;  
 thermally conductive plastic molded around the coils including the end coils; and  
 at least one feature pre-formed of material having a thermal conductivity higher than that of the thermally conductive plastic insert molded on at least one of the end coils when the plastic is molded so that it is disposed on an outer surface of the end coil.  
 
     
     
       16. The apparatus of  claim 15  wherein the feature includes at least one end cap. 
     
     
       17. The apparatus of  claim 16  wherein the feature further includes a fan. 
     
     
       18. apparatus of  claim 15  wherein the feature includes fins. 
     
     
       19. The apparatus of  claim 15  wherein the slots of the lamination stack includes slot liners made of thermally conductive plastic. 
     
     
       20. The apparatus of  claim 15  wherein the magnet wires have a layer of heat activated adhesive thereon, the thermally conductive plastic molded around the magnet wires and the heat of the thermally conductive plastic as it is molded activating the heat activated adhesive on the magnet wires and bonding the magnet wires together. 
     
     
       21. The apparatus of  claim 15  wherein at least one fan is formed of conductive plastic when the thermally conductive plastic is molded to at least partially encase the magnet wires.